The present invention relates to a combined type electromagnetic relay such as a twin type electromagnetic relay in which a plurality of electromagnetic blocks are joined to one another. The present invention relates, in particular, to a complex type electromagnetic relay in which electromagnetic blocks are stably joined to one another with a reduced number of components.
Conventionally, there has been an electromagnetic relay that has a structure in which two electromagnetic blocks are housed in one casing and a fixed contact (Normal Open -NO- contact or Normal Close -NC- contact) which is provided for each of the electromagnetic blocks is electrically connected to a common fixed terminal. This type relay is called a twin type. If this twin type electromagnetic relay is employed, then an electrical circuit for controlling forward and reverse currents to an electric load to achieve, for example, the forward and reverse rotation of a motor or the forward and reverse operation of a solenoid can be simply constructed.
That is, for example, the fixed terminal located on the NO contact side is connected to a power line, and the fixed terminal located on the NC contact side is connected to a ground line. Further, common terminals (movable contact terminals) which are connected to the movable contacts of the respective electromagnetic blocks are separately connected to one terminal side and the other terminal side of the motor coil. Then, the coil terminal of either one of the electromagnetic blocks is electrified with an excitation current according to a switch operation or a microcomputer output for instructing the forward or reverse rotation of the motor. This arrangement allows the bidirectional electrification control of the motor coil (i.e., the forward/reverse rotation control of the motor) to be achieved.
It is to be noted that the term of xe2x80x9celectromagnetic blockxe2x80x9d in the present specification means a sub-assembly which is consisted of a pair of basic elements each constituting an electromagnetic relay (the element including at least a movable contact, an electromagnet for effecting an electromagnetic force on the movable contact and a movable contact spring for effecting a restoration force on the movable contact).
At this type of electromagnetic relay has been known and disclosed in the prior art reference Japanese Utility Model Registration No. 2522448 or Japanese Utility Model Laid-Open Publication No. HEI 4-27547 (referred to as a xe2x80x9cfirst prior art examplexe2x80x9d hereinafter), the one disclosed in the prior art reference of Japanese Patent Laid-Open Publication No. HEI 10-1622712 (referred to as a xe2x80x9csecond prior art examplexe2x80x9d hereinafter) and the one disclosed in the prior art reference of Japanse Utility Model Laid-Open Publication No. SHO 63-23755 (referred to as a xe2x80x9cthird prior art examplexe2x80x9d hereinafter).
Among these, the first prior art example and the second prior art example are each provided with a joint member (a member independent of the fundamental member such as spools and terminals) called the base, fixed block or terminal assembly for stably and accurately connecting and fastening the electromagnetic blocks to the common fixed terminal. In the third prior art example, the upper flanges of the electromagnetic blocks, spools are joined together by the fixed terminal without providing any independent joining member.
In general, with regard to the electromagnetic relay mounted on an in-car circuit board, a relay of a sealed type (i.e., a sealed type relay) is commonly used. This type is selected so as to withstand the cleaning and the like after the mounting of the circuit board and securing specified waterproof and dustproof properties. For example, the relays of the aforementioned first and second prior art reference examples are each covered with a casing that is wholly closed except for one opened side on which terminal lead portions are exposed. The opened side of the casing is further covered with a member such as the base with a slight gap, and the opened side is sealed with a seal material.
Lately, there has been and earnest demand for the reducing the size and cost of the electromagnetic relays of this type. For these purposes, a further reduction in the number of components and a denser component assembly structure become important. Accordingly, in the aforementioned second prior art example, the member which is called the base that has conventionally been the base of the assembly is removed. Futher, there is used a relay of a type such that one flange of the spool around which the electromagnet coil is wound is arranged inside the opening of the casing and this one flange is made to concurrently function as a base.
However, the relay units of the first prior art example and the second prior art example are each provided with the joint member independent of the fundamental members such as the spools and the terminals. Therefore, the relay units of the first and second prior art examples have had the disadvantage that the components and the assembly processes are increased. Then the component cost and assembling cost rise.
The relay of the third prior art example has a structure in which the electromagnetic blocks are mutually assembled by joining only the flanges located on the upper side of the spools. Therefore, with the relay of the third prior art example it is difficult to assure a high assembling accuracy of the electromagnetic blocks and a high assembling accuracy of the fixed terminal.
Accordingly, it is a principal objective of the present invention to provide a complex type electromagnetic relay in which a plurality of electromagnetic blocks are joined in parallel to one another, the relay having a reduced number of components and a simple structure in which the electromagnetic blocks and the fixed terminals are stably joined to one another with high accuracy. It is a second object of the present invention to provide a complex type electromagnetic relay with a simple structure that can be wholly sealed (for the provision of a sealed type relay).
In order to achieve the aforementioned objectives, the first inventive aspect is to provide an electromagnetic relay of a complex type comprising: a plurality of electromagnetic blocks which are arranged in parallel to one another and each of which includes an electromagnet constructed of a coil wound around a spool which has flanges at both ends, a movable contact to be displaced in one direction by an effect of an electromagnetic force of one electromagnet, a movable contact spring for creating a restoration force toward the opposite direction on the movable contact, a common terminal connected to the movable contact and coil terminals connected to the coil; fixed contacts that are arranged on either side or oppositely on both sides of what in the direction of displacement of each movable contact and have the state of the connection changed relative to the movable contacts according to the displacement of the movable contacts; common fixed terminals connected to the respective fixed contacts each being arranged on an identical side relative to the movable contacts; and a common displacement regulating member that is provided when the fixed contacts are arranged on either side of the movable contacts so as to be arranged on the other side of the movable contacts as the need arises and regulates the displacement of the movable contacts toward the other side, the electromagnetic blocks being integrally joined to one another with the flanges located at both ends of the spools joined parallel to one another by mounting in an engagement manner the fixed terminals or the displacement regulating member on the flanges located on one side of the spools or the flanges located on the other side of the spools.
According to the electromagnetic relay of the present invention, the necessary fixed terminal and displacement regulating function as a joint member as well as joining the flanges which are located on both sides of the spool. With this arrangement, the stable high-accuracy assembling of the two electromagnetic blocks and the stable high-accuracy assembling of the fixed terminals with the electromagnetic blocks are achieved with a minimum number of components without providing any other members. As a result, there can be obtained the excellent effect of allowing the cost reduction to be achieved in terms of both the component cost and assembling cost while maintaining high reliability of the relay in a satisfactorily assembled state.
The electromagnetic relay of the second inventive aspect is characterized in that the engagement is put into effect by inserting or press-fitting projecting portions provided in a plurality or portions of the fixed terminals or the displacement regulating member into recess portions provided on the flanges located on one side of the spools or the flanges located on the other side of the spools.
The above arrangement allows the mounting to be easily achieved and allows the assembling cost to be further reduced, as compared with the case where the fixed terminals are mounted in an engagement manner on the flanges by, for example, crimping.
The electromagnetic relay of the third inventive aspect is characterized in that all elements except for the connecting end portions of the terminals are covered with a casing which is opening on one end side, the joined flanges located on one side of the spools have a shape and dimensions approximately equal to a shape and dimensions of the opening portion of the casing and are arranged inside the opening portion of the casing, the connecting end portions are led from the opening side of the casing, and the opening of the casing is closed with a gap that can be sealed with a seal member by the lead portions of the connecting end portions and the joined flanges located on one side of the spools.
The above arrangement also allows the obtainment of the effect that a high-reliability sealed relay of a complex type (a twin type, for example) is capable of easily being sealed with the seal member, without causing the deficiency of the excessive inflow of the seal member to the inside, and can be easily manufactured at low cost.